Rotary cutting tools can be provided with a threaded coupling mechanism, or “tool joint”, for securely retaining a replaceable cutting head within a tool holder.
The replaceable cutting head can include a male coupling member and the tool holder can include a female coupling member. The male coupling member can include an external thread. The female coupling member can include an internal thread that corresponds to the external thread on the male coupling member.
In some such rotary cutting tools, the internal and external threads are both straight threads. An example of such a rotary cutting tool is disclosed in, for example, U.S. Pat. No. 6,485,220.
In other such rotary cutting tools, the internal and external threads are both tapered threads. Examples of such a rotary cutting tool are disclosed in, for example, U.S. Pat. Nos. 7,611,311 and 7,713,004.